Hydrogen Selective NH2‐MIL‐53(Al) MOF Membranes with High Permeability

Abstract Hydrogen‐based energy is a promising renewable and clean resource. Thus, hydrogen selective microporous membranes with high performance and high stability are demanded. Novel NH 2 ‐MIL‐53(Al) membranes are evaluated for hydrogen separation for this goal. Continuous NH 2 ‐MIL‐53(Al) membranes have been prepared successfully on macroporous glass frit discs assisted with colloidal seeds. The gas sorption ability of NH 2 ‐MIL‐53(Al) materials is studied by gas adsorption measurement. The isosteric heats of adsorption in a sequence of CO 2 > N 2 > CH 4 ≈ H 2 indicates different interactions between NH 2 ‐MIL‐53(Al) framework and these gases. As‐prepared membranes are measured by single and binary gas permeation at different temperatures. The results of singe gas permeation show a decreasing permeance in an order of H 2 > CH 4 > N 2 > CO 2 , suggesting that the diffusion and adsorption properties make significant contributions in the gas permeation through the membrane. In binary gas permeation, the NH 2 ‐MIL‐53(Al) membrane shows high selectivity for H 2 with separation factors of 20.7, 23.9 and 30.9 at room temperature (288 K) for H 2 over CH 4 , N 2 and CO 2 , respectively. In comparison to single gas permeation, a slightly higher separation factor is obtained due to the competitive adsorption effect between the gases in the porous MOF membrane. Additionally, the NH 2 ‐MIL‐53(Al) membrane exhibits very high permeance for H 2 in the mixtures separation (above 1.5 × 10 −6 mol m −2 s −1 Pa −1 ) due to its large cavity, resulting in a very high separation power. The details of the temperature effect on the permeances of H 2 over other gases are investigated from 288 to 353 K. The supported NH 2 ‐MIL‐53(Al) membranes with high hydrogen separation power possess high stability, resistance to cracking, temperature cycling and show high reproducibility, necessary for the potential application to hydrogen recycling.